The present invention relates to control networks, and in particular, to systems and methods for analyzing control networks.
Industrial controllers, such as Programmable Logic Controllers (PLC's), are specialized electronic computer systems used for the control of industrial processes or machinery, for example, in a factory environment. Industrial controllers differ from conventional computers in a number of ways. Physically, they are constructed to be substantially more robust against shock and damage and to better resist external contaminants and extreme environmental conditions. The processors and operating systems are optimized for real-time control and execute languages allowing ready customization of programs to comport with a variety of different controller applications. Industrial controllers may have a user interface for accessing, controlling and/or monitoring the industrial controller, such as through a locally or remotely connected terminal(s) having a keyboard, mouse and display.
Typically, industrial controllers have a highly modular architecture that allows different numbers and types of network cards or adapters to be used to connect the controllers to the process or machinery to be controlled through special. “control networks” suitable for highly reliable and available real-time communication. Such control networks commonly used in industrial control systems include, for example, ControlNet, DeviceNet, EtherNet/IP and Sercos, whose specifications are published and whose protocols are used broadly by a number of manufacturers and suppliers. Control networks differ from standard communication networks, such as Ethernet, by guaranteeing maximum communication delays. This may be obtained, for example, by pre-scheduling the bandwidth of the network and/or providing redundant communication capabilities to high-availability. Control networks also differ from one another in physical aspects, for example, the type of media (e.g., co-axial cable, twisted pair, light fiber, wireless communications, etc.), the protocols of its operation, (e.g., Baud rate, number of channels, word transmission size, use of connected messaging, solicited and unsolicited messaging, etc.) and how the data is formatted and how it is collected into standard messages.
As part of their enhanced modularity, industrial controllers may employ one or more industrial devices coupled through the control networks. Industrial devices may comprise one or more I/O modules, AC/DC drives, motion drives or other hardware devices dedicated to a particular type of industrial function, for example, detecting input AC or DC signals or controlling output AC or DC signals in conjunction with an industrial process, or running motors or other machinery. Each I/O module or drive may have a connector system allowing them to be installed in different combinations in an industrial device along with other selected I/O modules or drives to match the demands of the particular application. Multiple industrial devices may be located at convenient control points near the controlled process or machine to communicate with the industrial controller via the control network.
Industrial controllers and/or industrial devices may be added, removed and/or updated periodically throughout a factory environment. For example, a new industrial process may be added via a new industrial device to increase the capability or the capacity of the industrial system. Similarly, an existing industrial controller and/or industrial device in an industrial system may be modified to include updated hardware or updated firmware. In some applications, industrial controllers and/or industrial devices must also be added, removed and/or updated while the industrial system is actively running. This may occur, for example, when interrupting the process would cause costly downtime and/or product defects. Consequently, the industrial system may typically change over time and throughout physically dispersed areas throughout the operating geography or in the factory.
U.S. patent application Ser. No. 13/528,198, titled “Industrial Hardware installation Base Reporting and Failure Monitoring,” assigned to the present assignee and incorporated herein by reference in its entirety, discloses an apparatus and method for automatically retrieving installation information for devices in a network. Here, installation information for a system, including device name, hardware area location including node number or IP address, serial number, manufacturing date, product type, device code, hardware description, firmware revision, major and minor fault flag, slot number and important condition monitoring parameters, may be automatically found in the system.
What is needed is an improved system for analyzing control networks with maximum speed and minimum intrusiveness. Moreover, what is needed is a technique for accurately determining resource utilization for control networks in order to provide diagnostic and reliability (DR) services.